A light emitting device using a light emitting diode (LED) is made generally of a combination of an LED chip as an excitation light source and a phosphor which is excited by the excitation light. Depending on kinds of the LED chip and the phosphor, various luminous colors can be realized.
For a white LED light emitting device emitting white light, for an example, a combination of a blue LED emitting blue light with a phosphor has been used. As the phosphor, a yellow phosphor is mainly used because the yellow color is a complementary color of a blue color. As another example, there is a white LED using the combination of the blue LED emitting the blue light with at least two phosphors selected from a green phosphor, a yellow phosphor, and a red phosphor.
With respect to the white light emitting device, in order to achieve a color close to that of natural light, it is desired to realize a high color rendering property, in particular, a high average color rendering index (Ra).